Northside Health Library

Methylmalonic acidemia

Definition

Methylmalonic acidemia is a disorder, passed down through families, in which the body cannot break down certain proteins and fats. The result is a build up of a substance called methylmalonic acid in the blood.

It is considered an inborn error of metabolism.

Causes

The disease is usually diagnosed in the first year of life. It is an autosomal recessive disorder, which means the defective gene must be passed onto the child from both parents.

About 1 in 25,000 - 48,000 babies are born with this condition. However, the actual rate may be higher, because a newborn may die before the condition is ever diagnosed. Methylmalonic acidemia affects boys and girls equally.

Symptoms

The disease can cause seizures and stroke. Babies may appear normal at birth, but develop symptoms once they start eating more protein, which can cause the condition to get worse.

Symptoms include:

Brain disease that gets worse (progressive encephalopathy)

Dehydration

Developmental delays

Failure to thrive

Lethargy

Repeated yeast infections

Seizures

Vomiting

Exams and Tests

Testing for methylmalonic acidemia is often done as part of a newborn screening exam. The U.S. Department of Health and Human Services recommends screening for this condition at birth because early detection and treatment has been shown to be beneficial.